Method for manufacturing light emitting device and light emitting device

ABSTRACT

A manufacturing method of a light emitting device includes a light emitting element disposed over a substrate and a reflective resin disposed along the side surface of the light emitting element. The method includes disposing light emitting elements in a matrix over an aggregate substrate, and disposing a semiconductor element between the adjacent light emitting elements in one direction of column and row directions of the light emitting elements in the matrix. A reflective resin is disposed to cover the semiconductor elements along the side surfaces of the light emitting elements and the side surfaces of the phosphor layers. The reflective resin and the substrate disposed in between the adjacent light emitting elements is cut in the column or row direction and between the light emitting element and the adjacent semiconductor element in the other direction, to include a light emitting element or a semiconductor element.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for manufacturing a lightemitting device that can be used for a display device, an illuminationtool, a display, a backlight source of a liquid crystal display, and thelike, and a light emitting device manufactured using the same.

2. Description of Related Art

Light emitting diodes (LED) having received attention as anext-generation light source have excellent effect of energy saving ascompared to an existing light source, and will be able to besemipermanently used. Applications of the light emitting diode, forexample, including a backlight, a vehicle, a lighting board, a trafficlight, and a general illuminating light, have been spread industry-wide.

One of the well-known light emitting devices using the LED includes alight emitting element mounted on a mounting substrate with wirings. Inrecent years, the so-called chip scale package (CSP), that is, a packagehaving substantially the same size as a light emitting element, and aplanar light emitting device including light emitting elements mountedat a high density have been developed.

By way of such a light emitting device, in order to ensure a high frontsurface brightness, the light emitting device is proposed which includesa light emitting element, a wavelength conversion layer disposed overthe light emitting element for converting a wavelength of the light fromthe light emitting element, the conversion layer being formed of atranslucent member including a phosphor, and a reflection memberdisposed adjacent to the side surface of the wavelength conversion layerand the side surface of the light emitting element (for example, JP2009-218274 A).

FIG. 11 is an exemplary diagram of an example of one step of amanufacturing method of a light emitting device in the related art,showing a plurality of light emitting devices manufactured. A pluralityof light emitting elements 53 are flip-chip mounted over a substrate 52via bumps 60. A phosphor layer 54 forming a light emitting surface ofthe light emitting device is bonded to the upper surface of each lightemitting element 53 using a phosphor layer adhesive 56. The lightemitting element 53 and the phosphor layer 54 are sealed with areflective resin 58.

However, in an intermediate region 61 between the adjacent lightemitting elements 53, a recessed portion, which is the so-called “sink”,is generated due to hardening and contraction of the reflective resin58. In particular, the largest intermediate region 61, that is, a regionhaving the maximum distance between the adjacent light emitting elements53 tends to generate the sink. As the sink becomes larger, the width ofthe reflective layer on each side surface of the phosphor layer 54 isthinned, which cannot sufficiently reflect the light from the phosphorlayer 54, resulting in a decrease in light-extraction efficiency. Thismight make the light emitted from a light emitting surface non-uniform,or render an end of the light emitting surface vague, thus leading todegradation of light quality.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide amethod for manufacturing a light emitting device, and a light emittingdevice manufactured by the method that can improve the light-extractionefficiency by suppressing the sink of the reflective resin andincreasing the thickness of the reflective layer on the side surface ofthe phosphor layer.

In order to solve the above problems, the inventors have intensivelystudied and found that a semiconductor element can be disposed betweenthe adjacent light emitting elements to suppress the sink of thereflective resin. Based on the findings, the present invention has beenmade.

That is, a method for manufacturing a light emitting device according toone embodiment of the invention is a manufacturing method of a lightemitting device which includes a light emitting element disposed over asubstrate and a reflective resin disposed along the side surface of thelight emitting element. The method includes the steps of: disposinglight emitting elements in a matrix over an aggregate substrate, anddisposing a semiconductor element between the adjacent light emittingelements in one of column and row directions of the light emittingelements in the matrix; after disposing phosphor layers over therespective upper surfaces of the light emitting elements, disposing areflective resin along the side surfaces of the light emitting elementsand the side surfaces of the phosphor layers to cover the semiconductorelements; and simultaneously cutting the reflective resin and thesubstrate disposed in between the adjacent light emitting elements inone direction of the column and row directions and between the lightemitting element and the semiconductor element adjacent thereto in theother direction so as to include at least one light emitting element andone semiconductor element.

That is, a method for manufacturing a light emitting device according toanother embodiment of the invention is a manufacturing method of a lightemitting device which includes a light emitting element disposed over asubstrate and a reflective resin disposed along the side surface of thelight emitting element. The method includes the steps of: disposing aplurality of light emitting elements in a matrix over an aggregatesubstrate, and disposing a semiconductor element other than the lightemitting element in between the adjacent light emitting elements in oneof column and row directions of the light emitting elements disposed inthe matrix; disposing translucent members each having a phosphor layerpreviously formed on a front surface thereof, over the respective lightemitting elements with the phosphor layer facing the upper surface ofthe light emitting element; disposing a reflective resin along the sidesurfaces of the light emitting elements, side surfaces of the phosphorlayers, and the translucent members to cover the semiconductor elements;and simultaneously cutting the reflective resin and the substratedisposed in between the adjacent light emitting elements in one of thecolumn and row directions and between the light emitting element and theadjacent semiconductor element in the other direction so as to includeat least one light emitting element and one semiconductor element.

A light emitting device according to a further embodiment of theinvention includes a light emitting element disposed over a substrate; aphosphor layer disposed over the light emitting element; a semiconductorelement disposed adjacent to the light emitting element; and areflective resin disposed along the side surfaces of the light emittingelement and the phosphor layer to cover the semiconductor element. Acorner formed by a side surface of the reflective resin on thesemiconductor element side and an upper surface of the reflective resinforms an acute angle in a vertical cross-sectional view including thelight emitting element and the semiconductor element.

Accordingly, the invention can provide a light emitting device withimproved light-extraction efficiency by increasing the thickness of thereflective layer on the side surface of the phosphor layer bysuppressing the sink of the reflective resin.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic cross-sectional view showing an example of onestep in a manufacturing method according to a first embodiment of theinvention.

FIG. 1B is a schematic cross-sectional view showing an example ofanother step in the manufacturing method in the first embodiment of theinvention.

FIG. 2 is an exemplary top view showing an example of another step inthe manufacturing method in the first embodiment of the invention.

FIG. 3A is an exemplary top view showing an example of a light emittingdevice manufactured using the manufacturing method according to thefirst embodiment of the invention.

FIG. 3B is a schematic cross-sectional view showing the example of thelight emitting device manufactured using the manufacturing method in thefirst embodiment of the invention.

FIG. 4 is an enlarged view of FIG. 3B.

FIG. 5A is an exemplary top view showing an example of a light emittingdevice according to a second embodiment of the invention.

FIG. 5B is a schematic cross-sectional view showing the example of thelight emitting device in the second embodiment of the invention.

FIG. 5C is an exemplary enlarged partial cross-sectional view showingthe example of the light emitting device in the second embodiment of theinvention.

FIG. 6A is a schematic cross-sectional view showing an example of onestep in a manufacturing method according to the second embodiment of theinvention.

FIG. 6B is a schematic cross-sectional view showing an example ofanother step in the manufacturing method in the second embodiment of theinvention.

FIG. 6C is a schematic cross-sectional view showing an example ofanother step in the manufacturing method in the second embodiment of theinvention.

FIG. 7 is a schematic cross-sectional view showing another example ofthe light emitting device according to a third embodiment of theinvention.

FIG. 8A is a schematic cross-sectional view showing an example of onestep in a manufacturing method according to the third embodiment of theinvention;

FIG. 8B is a schematic cross-sectional view showing an example ofanother step in the manufacturing method in the third embodiment of theinvention.

FIG. 8C is a schematic cross-sectional view showing an example ofanother step in the manufacturing method in the third embodiment of theinvention.

FIG. 9A is a photograph showing the state of a light emitting surface ofExample 1.

FIG. 9B is a photograph showing the state of a light emitting surface ofComparative Example 1.

FIG. 10 is a cross-sectional photograph showing the state of the lightemitting surface of Example 1.

FIG. 11 is an exemplary cross-sectional photograph showing one step of aconventional manufacturing method.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will be described belowwith reference to the accompanying drawings. The terms “upper” and“lower” as used in the present application are used to indicate the sidefrom which light emitted from a light emitting device is extracted, andthe opposite side thereto. For example, the term “upward” as used hereinmeans the direction in which the light emitted from the light emittingdevice is extracted, and the term “downward” as used herein means theopposite direction thereto. The term “upper surface” as used hereinmeans a surface on the side from where the light emitted from the lightemitting device is extracted, and the term “lower surface” as usedherein means the opposite surface thereto.

First Embodiment

A method for manufacturing a light emitting device according to thisembodiment includes the steps of: disposing a plurality of lightemitting elements in a matrix over an aggregate substrate, and disposinga semiconductor element other than the light emitting element in betweenthe adjacent light emitting elements in one of column and row directionsof the light emitting elements disposed in the matrix; after disposingphosphor layers over the upper surface of the light emitting elements,disposing a reflective resin to cover the semiconductor elements alongthe side surfaces of the light emitting elements and the side surfacesof the phosphor layers; and simultaneously cutting the reflective resinand the substrate disposed in between the adjacent light emittingelements in one direction of the column and row directions and betweenthe light emitting element and the adjacent semiconductor element in theother direction so as to include at least one light emitting element andone semiconductor element.

FIGS. 1A and 1B show exemplary diagrams of an example of steps in themanufacturing method of a light emitting device in this embodiment.Referring to FIG. 1A, a plurality of light emitting elements arearranged in a matrix over an aggregate substrate, and a semiconductorelement is disposed between the adjacent light emitting elements in onedirection of the column and row directions of the light emittingelements disposed in the matrix. Methods for arranging the lightemitting elements and the semiconductor elements for use can includeflip-chip mounting. Conductive patterns including a positive electrodeand a negative electrode insulated from each other are formed over thesubstrate 2. The flip chip mounting is a mounting method formechanically and electrically coupling the light emitting elements tothe conducive patterns of a base substrate by bonding and opposing theelectrodes of the light emitting elements to the conductive patterns viaconductive members, such as bumps. In mounting, the bump may be providedon the substrate, or on the light emitting element and semiconductorelement.

Then, p and n electrodes (not shown) of a light emitting element 3 arerespectively opposed to both the positive and negative electrodes (notshown) formed on the same surface of the substrate 2 and fixed to theelectrodes via conductive members 10. The respective electrodes of thelight emitting element 3 are opposed to the conductive members 10 byapplying heat, ultrasound wave, and loads, so that the light emittingelements 3 are bonded to the conductive members 10.

In a step shown in FIG. 1B, after disposing phosphor layers over therespective upper surfaces of the light emitting elements, a reflectiveresin is disposed along the side surfaces of the light emitting elementsand the side surfaces of the phosphor layers to cover the semiconductorelements. A reflective resin 8 is to reflect the light emitted from thelight emitting elements 3. The reflective resin 8 is disposed over theside surfaces of the light emitting elements 3 and over the sidesurfaces of phosphor layers 4 to thereby cover the entire semiconductorelements 5. The semiconductor element 5 is disposed in an intermediateregion 11 between the adjacent light emitting elements 3, therebysuppressing the sink of the reflective resin 8. As a result, the widthof the reflective layer on each side surface of the phosphor layer 4becomes thicker, which can sufficiently reflect the light from thephosphoric layer 4, thus improving the light-extraction efficiency.Underfill material (not shown) may be charged into gaps between thelight emitting element 3 and semiconductor element 5, and the conductivemember 10.

Then, in a next step (not shown), the reflective resin and the substrateare simultaneously cut along a cutting line 12 shown in FIG. 1B and FIG.2 between the adjacent light emitting elements in one direction of thecolumn and row directions and between the light emitting element and theadjacent semiconductor element in the other direction to include atleast one light emitting element and one semiconductor element, so thatindividual light emitting devices are separated from a group of lightemitting devices.

In this way, the light emitting device can be manufactured which hasimproved light-extraction efficiency by suppressing the sink of thereflective resin.

(Substrate)

Suitable materials for the substrate are preferably insulatingmaterials, specifically, materials which are less likely to allow lightfrom the light emitting element or external light to pass through thematerial. For example, the suitable materials for the substrate caninclude ceramic, such as alumina or aluminum nitride, resin, such asphenol resin, epoxy resin, polyimide resin, BT resin, orpolyphthalamide, and the like. In use of the resin, if necessary,inorganic filler, such as glass fiber, silicon oxide, titanium oxide, oralumina, can be mixed into the resin. This mixture can improve themechanical strength and the light reflectivity, and reduce the thermalexpansion rate.

(Light Emitting Element)

The light emitting element 3 is preferably a light emitting diode, andcan select an arbitrary wavelength according to application. Forexample, the light emitting element 3 can preferably include a nitridesemiconductor (In_(x)Al_(y)Ga_(1-x-y)N, 0≦x, 0≦Y, X+Y≦1) that can emitlight having a short wavelength that enables the effective excitation ofphosphor material. Various wavelengths of the light to be emitted can beselected according to the material or the mixed crystal degree of thesemiconductor layer.

(Phosphor Layer)

The phosphor layer 4 absorbs at least a part of light emitted from thelight emitting element 3 to generate light having a differentwavelength. The phosphor layer can include, for example, a piece cutfrom a phosphor ingot made of phosphor single crystal, or polycrystal,or a sintered body of phosphor powder, or a piece molded using a mixtureof the phosphor material and a translucent material made of resin,glass, or inorganic material. The phosphor layer may be formed in asingle layer of one kind of material or two or more kinds of materials,or may be formed of a laminated layer with two or more layers. Thephosphor layer may be a translucent member made of glass or resin with aphosphor layer formed on its front surface. A diffusing agent may beadded to the phosphor layer if necessary.

In the invention, in order to suppress the sink of the reflective resin,it is necessary to heighten the upper surface of the reflective resin bycompletely embedding the semiconductor elements in the reflective resin.For this reason, the upper surface (light emitting surface) of thephosphor layer needs to be at a higher level than the upper surface ofthe semiconductor element.

Typical phosphor materials that can emit a white mixed-colored lightbeam in combination with the use of a blue light emitting element caninclude, for example, an yttrium aluminum garnet phosphor (YAGphosphor). When setting the light emitting device that can emit whitelight, the concentration of phosphor materials contained in the phosphorlayer is adjusted so as to emit the white light. The concentration ofthe phosphor materials is in a range of, for example, about 5 to 50%.

Alternatively, a blue light emitting element is used as the lightemitting element, and a combination of a YAG phosphor and a nitridephosphor containing a predominant amount of a red component is used asthe phosphor member, which can emit umber light. The umber colorcorresponds to a region comprised of a long-wavelength region of yellowdefined by JIS Z8110 and a short-wavelength region of yellow-red, or achromaticity range sandwiched between a range of yellow as a safe colordefined by JIS Z9101 and the short-wavelength range of yellow-red. Theumber color corresponds to a region positioned at a dominant wavelengthof 580 to 600 nm.

The YAG phosphor is a general name for a garnet structure containing Yand Al. The YAG phosphor is a phosphor activated by at least one elementselected from rare-earth elements, and serves to emit the light by beingexcited by a blue light beam emitted from the light emitting element.The YAG phosphor can include, for example,(Re_(1-x)Sm_(x))₃(Al_(1-y)Ga_(y))₅O₁₂:Ce (0≦x<1, 0≦y≦1, in which Re isat least one element selected from the group consisting of Y, Gd, andLa).

The nitride phosphor is a phosphor containing N, at least one group IVelement selected from the group consisting of C, Si, Ge, Sn, Ti, Zr, andHf, and at least one group II element selected from the group consistingof Be, Mg, Ca, Sr, Ba, and Zr, which is activated by at least one rareearth element selected from the group consisting of Y, La, Ce, Pr, Nd,Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu. The composition of the nitridephosphor may contain O.

Specifically, the nitride phosphor can be represented by a generalformula L_(x)M_(y)N_(((2/3)x+(3/4)Y)):R, orL_(x)M_(y)O_(z)N_(((2/3)x+(4/3)Y−(2/3)Z)):R (in which L is at least onegroup II element selected from the group consisting of Be, Mg, Ca, Sr,Ba, and Zn; M is at least one group IV element selected from the groupconsisting of C, Si, Ge, Sn, Ti, Zn, and Hf; and R is at least onerare-earth element selected from the group consisting of Y, La, Ce, Pr,Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu. X, Y, and Z satisfy thefollowing relations: 0.5≦X≦3, 1.5≦Y≦8, 0<Z≦3).

(Semiconductor Element)

The semiconductor elements 5 are disposed adjacent to the light emittingelements 3 over the substrate 2, separately from the light emittingelement 3. Any member that can heighten the upper surface of thereflective resin 8 up to the upper surface of the phosphor layer 4 canbe used in place of the semiconductor element, but the semiconductorelement can be normally used. Such semiconductor elements can includeanother light emitting element not intended for light emission of thelight emitting device, a transistor for controlling the light emittingelement, and a protective element to be described below. The protectiveelement is an element for protecting the light emitting element 3against element breakdown or performance degradation due to excessiveapplied voltage. The protective element is specifically comprised of aZener diode which is designed to be energized when a predeterminedvoltage or more is applied thereto. The protective element is asemiconductor element having p and n electrodes, like the light emittingelement 3, and is arranged in antiparallel to p and n electrodes of thelight emitting element 3. That is, the n and p electrodes of the lightemitting element 3 are electrically connected to the p and n electrodesof the protective element via the conductive member 10. Like the lightemitting element, the respective electrodes of the protective elementare opposed to over the conductive members by applying heat, ultrasoundwave, and loads, like the light emitting element, so that the protectiveelements are bonded to the conductive members.

Thus, even when an excessive voltage is applied to between both p and nelectrodes of the light emitting element 3 and intends to exceed a Zenervoltage of the Zener diode, the voltage between both p and n electrodesof the light emitting element 3 is kept to the Zener voltage, and neverexceed the Zener voltage. The provision of the protective element canprevent the voltage between both p and n electrodes from reaching theZener voltage or more, and thus can appropriately prevent the elementbreakdown and performance degradation of the light emitting element 3due to the excessive applied voltage.

The height of the semiconductor element in mounting needs to be lowerthan that of the combination of the light emitting element and thephosphor layer. This is because the semiconductor element is completelyembedded in the reflective resin to increase the upper surface of thereflective resin, thereby suppressing the sink of the resin.

FIG. 2 is a top view of the group of the light emitting devices disposedover the aggregate substrate in the step of FIG. 1B. Referring to FIG.2, the upper surfaces 4 a of the phosphor layers are arranged in thecolumn and row directions over the substrate. The upper surface 4 aforms the light emitting surface of each of the light emitting devices.The semiconductor elements are completely embedded in the reflectiveresin, and thus cannot be observed. However, an intermediate region isdisposed between the adjacent two light emitting elements in the rowdirection. Preferably, the intermediate region for disposing thesemiconductor element therein is an intermediate region disposed betweenthe light emitting element and another adjacent light emitting elementhaving a larger one of a distance between the adjacent light emittingelements in one direction of the column and row directions and adistance between the adjacent light emitting elements in the otherdirection. This is because the sink of the reflective resin tends to begenerated in the intermediate region. Referring to FIG. 2, a distance Xin the row direction is larger than a distance y in the columndirection. In this case, the semiconductor element is disposed in theintermediate region in the row direction. Within a region surroundingthe light emitting element defined by the cutting line 12 of FIG. 2, thearea of a surrounding region except for a region where the semiconductorelement is disposed should be as small as possible because thisarrangement can suppress the sink of the reflective resin in thesurrounding region.

(Reflective Resin)

Suitable material for the reflective resin 8 for use is preferablyinsulating material. In order to ensure adequate strength, for example,a thermosetting resin or thermoplastic resin can be used. Morespecifically, the resins can include phenol resin, epoxy resin, BTresin, PPA, and silicon rein. Powder made of reflective material (forexample, TiO₂, Al₂O₃, ZrO₂, MgO) having its refractive index largelydifferent from that of resin as a base and which is less likely toabsorb light from the light emitting element 3 is dispersed into theresin as the base, which can effectively reflect the light.

The reflective resin 8 can be charged, for example, by use of a resindischarge device that can be moved (operated) over the fixed substrate 2vertically or horizontally with respect to the substrate 2. That is, theresin discharge device with the resin charged therein is moved whiledischarging a liquid resin from a nozzle at a tip of the device, wherebythe reflective resin 8 is charged into the vicinity of the lightemitting element 3 and the semiconductor element 5. The moving velocityof the resin discharge device can be appropriately adjusted according tothe viscosity and temperature of the resin used. Adjustment of thedischarge amount can be performed by setting a pressure or the like atthe time of discharge to a certain level, or the like. The viscosity ofthe reflective resin at room temperature (20±5° C.) is in a range of0.35 to 13.0 Pa·s, and preferably in a range of 3.0 to 5.5 Pa·s.

(Conductive Member)

A conductive member for use can be bumps. Suitable materials for thebumps can include, Au, eutectic solder (Au—Sn), Pb—Sn, lead-free solder,and the like. Although FIGS. 1A and 1B show an example of use of thebumps as the conductive member, the conductive member is not limited tothe bump, and for example, may be a conductive paste.

(Underfill Material)

The underfill material is a member for protecting the light emittingelement, other semiconductor elements, and the conductive membersdisposed over the substrate against refuse, moisture, external force,and the like. The underfill material may be charged into gaps betweenthe light emitting element 3 and semiconductor element 5, and theconductive member 10 and the substrate 2 if necessary.

Suitable underfill materials can include, for example, silicone resin,epoxy resin, urea resin, and the like. In addition to such a material,the underfill material can contain a colorant, a light diffusing agent,a filler, a phosphor material, and the like if necessary.

FIGS. 3A and 3B are exemplary diagrams showing one example of thestructure of the light emitting device A manufactured using themanufacturing method of a light emitting device in this embodiment,while illustrating the state of the light emitting element and thesemiconductor element directly after cutting vertically. FIG. 3A is atop view thereof, and FIG. 3B is a cross-sectional view taken along lineX-X′ of FIG. 3A. The light emitting surface 4 a is formed of a part ofthe phosphor layer. The reflective resin layer 8 is provided in thelight emitting device. The light emitting device 1 includes thesubstrate 2, the light emitting elements 3 flip-chip mounted over thesubstrate 2 via the conductive members 10, each light emitting elementhaving the phosphor layer 4 over its upper surface, the semiconductorelements 5 flip-chip mounted over the substrate 2 via the conductivemembers 10, each semiconductor element being arranged in parallel to thelight emitting element 3, and the reflective resin 8 disposed along theside surfaces of the light emitting elements 3 and the phosphor layers 4to cover the entire semiconductor elements 5. As shown in FIGS. 3A and3B, one of the light emitting devices continuously arranged in rows iscut from an adjacent light emitting device in a continuous regiontherebetween in the row direction. FIG. 4 is an enlarged view of theexemplary cross-sectional view of FIG. 3B. The reflective resin 8 has anupper surface 8 a, a side surface 8 b on the semiconductor element 5side surface, and a side surface 8 c on the light emitting element 3side surface. An angle θ₁ indicates an angle of a corner 8 a 1 on thesemiconductor element 5 side surface formed by the side surface 8 b ofthe reflective resin 8 on the semiconductor element 5 side surface andthe upper surface 8 a of the reflective film 8. The corner 8 a 1 formsan acute angle in the vertical cross-sectional view including the lightemitting element 3 and the semiconductor element 5. Since the angle θ₁is the acute angle, the thickness of the reflective resin 8 covering thesemiconductor element 5 can be sufficiently ensured. In contrast, whenthe angle θ₁ is an obtuse angle, the reflective resin 8 covering thesemiconductor element 5 is thinned, so that the reflective resin mightdisadvantageously reduce the function of protecting the semiconductorelement 5 from external environment. On the other hand, an angle θ₂indicates an angle of a corner 8 a 2 on the light emitting element 3side surface formed by the side surface 8 c of the reflective resin 8 onthe light emitting element 3 side surface and the upper surface 8 a ofthe reflective film 8. The corner 8 a 2 forms the obtuse angle in thevertical cross-sectional view including the light emitting element andthe semiconductor element. As shown in FIG. 3B, in the cutting step ofthe manufacturing method of the light emitting device, when the angle θ₂is the obtuse angle, then the angle θ₁ at the side surface 8 b of thereflective resin 8 of another adjacent light emitting device becomes theacute angle, which is preferable. Further, a deepest part of a recessedportion (sink) formed at the upper surface of the reflective resin ispreferably formed directly above the semiconductor element. This isbecause, when the deepest part of the recessed portion is not locateddirectly above the semiconductor element, the reflective layer on theside surface of the phosphor layer 4 becomes thin, which is notpreferable. The deepest part is preferably formed directly above thecenter of the upper surface of the semiconductor element. Thisarrangement can suppress the thickness of the reflective layer on theside surface of the phosphor layer from being decreased, while ensuringthe thickness of the reflective resin for protecting the semiconductorelement.

The light emitting device 1 includes the thick reflective layer on theside surface of the phosphor layer 4 with little sink of the reflectiveresin 8, which can sufficiently reflect the light from the phosphorlayer 4. As a result, the light emitting device 1 can improve thelight-extraction efficiency.

Second Embodiment

The phosphor layer for use is produced by molding a mixture of thephosphor material and binder, such as resin or glass, into a plateshape. In order to adjust the light emission from the light emittingdevice to a desired chromaticity, it is often necessary to increase theamount of phosphor material contained in the phosphor layer. Methods forincreasing the amount of phosphor material include increasing theconcentration of phosphor material, and increasing the thickness of thephosphor layer. As the concentration of some phosphor materials selectedis increased, the phosphor layers made of the phosphor material mighthave its strength reduced. When the thickness of the phosphor layer isincreased, the thermal conductivity of the phosphor layer is reduced. Asa result, heat generated by the phosphor in the light conversion isstored in the phosphor layer, which might promote thermal degradation ofthe phosphor or binder, thereby reducing the intensity of fluorescence.However, this embodiment can decrease the thickness of the phosphorlayer to increase the concentration of the phosphor, in addition to theeffect of the first embodiment.

A method for manufacturing a light emitting device according to thisembodiment includes the steps of: disposing a plurality of lightemitting elements in a matrix over an aggregate substrate, and disposinga semiconductor element other than the light emitting element in betweenthe adjacent light emitting elements in one of column and row directionsof the light emitting elements in the matrix; disposing translucentmembers each having a phosphor layer previously formed over a frontsurface thereof, over the respective light emitting elements with thephosphor layer facing the corresponding upper surface of the lightemitting element; disposing a reflective resin along the side surfacesof the light emitting elements, the side surfaces of the phosphorlayers, and the translucent members to cover the semiconductor elements;and simultaneously cutting the reflective resin and the substrate inbetween the adjacent light emitting elements in one of the column androw directions and between the light emitting element and the adjacentsemiconductor element in the other direction so as to include at leastone light emitting element and one semiconductor element.

FIGS. 5A, 5B, and 5C are exemplary diagrams showing one example of thestructure of the light emitting device B manufactured by using amanufacturing method of a light emitting device according to thisembodiment. FIG. 5A shows an upper view of the light emitting device.FIG. 5B is a cross-sectional view taken along line X-X′ of FIG. 5A. FIG.5C is an enlarged cross-sectional view of an end of the bonding layer inFIG. 5B. The light emitting device B includes the substrate 2, the lightemitting element 3 flip-chip mounted over the substrate 2 via theconductive members 10, the phosphor layer 4 disposed over the uppersurface of the light emitting element 3 via an adhesive layer 6, atranslucent member 9 integrally disposed with the phosphor layer 4 overthe upper surface of the phosphor layer 4, and the reflective resin 8disposed along the side surfaces of the light emitting element 3, thephosphor layer 4, and the translucent member 9. The semiconductorelement 5 is disposed adjacent to the light emitting element 3.

In the light emitting device B, the phosphor layer 4 is integrallyformed with the translucent member 9, and the translucent member 9serves as a supporter for the phosphor layer 4. Thus, the thinnerphosphor layer 4 having a high concentration of phosphor material can beformed over the surface of the translucent member 9. With thisarrangement, even though the concentration of phosphor material is high,the thermal conductivity of the phosphor layer 4 can be improved withoutreducing the mechanical strength of the phosphor layer 4. The plane areaof each of the translucent member and the phosphor layer can be the sameas that of the upper surface of the light emitting element. Taking intoconsideration the mounting accuracy in the actual manufacturing step,when the plane area of each of the translucent member and the phosphorlayer is the same as that of the upper surface of the light emittingelement, the phosphor layer might not be disposed above a part of theupper surface of the light emitting element. In order to surely disposethe phosphor layer over the entire upper surface of the light emittingelement, the plane area of each of the translucent member and thephosphor layer is sometimes set larger than that of the upper surface ofthe light emitting element. In this case, the translucent membersupports the entire phosphor layer. When the phosphor layer positionedover the entire main surface of the translucent member is disposed overthe upper surface of the light emitting element, an outer periphery ofthe phosphor layer located outside the edge of the upper surface of thelight emitting element can also be stably supported without partly beingpeeled or broken.

(Substrate)

Material for the substrate 2 for use can be the same as that used in thefirst embodiment.

(Light Emitting Element)

The light emitting element 3 for use can be the same as that used in thefirst embodiment.

(Phosphor Layer)

The phosphor layer 4 absorbs at least a part of light emitted from thelight emitting element 3 to generate light having a differentwavelength. The phosphor layer 4 can be formed by molding a mixture of atranslucent material containing resin, glass, inorganic material, or thelike with a binder made of phosphor. The phosphor layer 4 may be formedin a single layer of one kind of material or two or more kinds ofmaterials, or may be formed of a laminated layer with two or morelayers. A diffusing agent may be added to the phosphor layer 4 ifnecessary. The phosphor layer 4 is preferably formed to have a largerarea than the area of the upper surface of the light emitting element 3.In this case, the phosphor layer 4 is disposed at the light emittingelement 3 such that an exposed part of the phosphor layer 4 not coveredby the upper surface of the light emitting element is formed as a partof the bonding surface of the phosphor layer with the light emittingelement.

The phosphor layer 4 is printed on the surface of a translucent membermentioned below. The phosphor layer of this embodiment is in directcontact with the surface of the translucent member, but is not limitedthereto. Alternatively, the phosphor layer may be bonded via anothermember, such as an adhesive. For example, the bonding ways can includepressure bonding, fusion bonding, sintering, bonding with an organicadhesive, bonding with an inorganic adhesive, such as a low-meltingpoint glass, and the like. Formation methods of the phosphor layer caninclude printing, compression molding, phosphor electrodeposition,phosphor sheet, and the like. The printing process involves preparing apaste containing a phosphor, a binder, and a solvent, applying the pasteto the surface of the translucent member, and then drying the paste toform the phosphor layer. The binders for use can include organic resinbinder, such as epoxy resin, silicone resin, phenol resin, and polyimideresin, and inorganic binder, such as glass. The compression moldinginvolves molding a material for the phosphor layer containing a phosphormaterial in a binder, on the surface of a translucent member by use of amold. The phosphor electrodeposition involves forming a conductive thinfilm that can be translucent, on the surface of the translucent member,and depositing a charged phosphor layer on the thin film byelectrophoresis. The phosphor sheet process involves mixing a phosphormaterial into a silicon resin, processing the mixture into a sheet-likephosphor, and press-bonding and integrating the thin phosphor sheet ofabout 100 μm or less in thickness with a translucent member for thepurpose of improving the heat dissipation property of heat from thephosphor. The phosphor sheet has any thickness as long as it issufficiently thin.

The thickness of the phosphor layer 4 is in a range of 20 to 100 μm, andpreferably 20 to 50 μm. When the phosphor layer 4 has a thickness ofmore than 100 μm, the heat dissipation property of the phosphor layertends to be reduced. As the phosphor layer is thinned, the heatdissipation property is preferably improved. However, the excessive thinphosphor layer contains a very small amount of phosphor material, whichtends to reduce a range of chromaticity of the emitted light ofinterest. Taking into consideration that aspect, the thickness of thephosphor layer 4 can be adjusted to an appropriate value.

A typical phosphor that can emit a white mixed-colored light beam inappropriate combination with the use of a blue light emitting elementis, for example, an yttrium aluminum garnet phosphor (YAG phosphor). Inuse of the light emitting device that can emit white light, theconcentration of the phosphor contained in the phosphor layer 4 isadjusted so as to emit the white light. The concentration of thephosphor is in a range of, for example, about 5 to 50%.

Alternatively, a blue light emitting element is used as the lightemitting element 3, and a YAG phosphor and a nitride phosphor containinga predominant amount of a red component are used as the phosphor, whichcan emit umber light. Most of the phosphor emitting the umber light hasa low light-conversion efficiency. In order to obtain the desired colortone, the concentration of the phosphor is desired to be increased. Sucha phosphor generates more heat than other phosphors, which is a bigproblem. This embodiment can increase the concentration of the phosphormaterial of the phosphor layer and can decrease the thickness of thephosphor layer. Thus, this embodiment can appropriately use the phosphoremitting the umber light.

The YAG phosphor and the nitride phosphor for use can be the same asthose used in the first embodiment.

(Translucent Member)

The translucent member 9 is a member separately provided from thephosphor layer containing the phosphor material. The translucent member9 is a supporter for supporting the phosphor layer formed at itssurface. The translucent member 9 for use can be a plate-like membermade of translucent material, such as glass or resin. Glasses can beselected from borosilicate glass, and quartz glass. Resin can beselected from silicone resin and epoxy resin. The translucent member 9may have any thickness as long as the translucent member can impart thesufficient mechanical strength to the phosphor layer 4 without reducingthe mechanical strength during the manufacturing process. The excessivethickness of the translucent member 9 fails to reduce the size of thelight emitting device or reduces the heat dissipation property. Thus,the translucent member 9 should have an appropriate thickness. The mainsurface of the translucent member is preferably larger than the size ofthe contour of the light emitting element. This is because, by providingthe phosphor layer over the entire main surface of the translucentmember, the phosphor layer can be surely disposed over the entire uppersurface of the light emitting element in disposing the translucentmember with the phosphor layer over the upper surface of the lightemitting element, even with a little deviation of mounting accuracy. Thediffusing agent may be contained in the translucent member 9. When theconcentration of phosphor material of the phosphor layer 4 is increased,color unevenness tends to be caused. However, the presence of thediffusing agent can suppress the unevenness of not only color but alsobrightness. The diffusing agent for use can be made of titanium oxide,barium titanate, aluminum oxide, silicon dioxide, and the like. Theupper surface of the translucent member 9 serving as the light emittingsurface is not limited to a flat surface, and may have fine asperities.The fine asperities on the surface can promote scattering of the lightemitted from the light emitting surface to thereby suppress theunevenness of brightness or color.

(Adhesive Layer)

The adhesive layer 6 intervenes in between the light emitting element 3and the phosphor layer 4 to fix the light emitting element 3 to thephosphor layer 4. The adhesive forming the adhesive layer 6 ispreferably made of material that can effectively guide the light emittedfrom the light emitting element 3 toward the phosphor layer 4, whileoptically coupling the light emitting element 3 to the phosphor layer 4.Specifically, suitable materials for the adhesive layer 6 can includeorganic resin, such as epoxy resin, silicon resin, phenol resin, orpolyimide resin, and preferably silicone resin. As the thickness of theadhesive layer is decreased, the adhesive layer exhibits its functionmore effectively. This is because the thinner adhesive layer improvesits heat dissipation property, and reduces the loss of light passingthrough the adhesive layer to improve the light output from the lightemitting device.

Preferably, the adhesive layer 6 exists not only between the lightemitting element 3 and the phosphor layer 4, but at the side surfaces ofthe light emitting element 3. The bonding layer on the side surfacereflects the light emitted from the side surface of the light emittingelement 3 to allow the light to enter the phosphor layer 4, therebyimproving the light-conversion efficiency of the phosphor. As shown inFIG. 5C, preferably, in the vertical cross-sectional view of the sidesurface of the light emitting element 3, the adhesive extends at acorner formed by the side surface of the light emitting element 3 andthe surface on the light emitting element side surface of the phosphorlayer 4. The extending adhesive layer preferably has a roughlytriangular cross section such that the thickness of the adhesive layeris decreased toward the lower part of the light emitting element 3. Apart of the reflective resin is preferably disposed to be in contactwith the adhesive layer having the roughly triangular cross section.Thus, the light emitted from the side surface of the light emittingelement 3 is reflected by an interface between the reflective resin andthe adhesive layer having the roughly triangular cross section. If thearea of the phosphor layer is increased to be larger than that of theupper surface of the light emitting element, the outer periphery of thephosphor layer 4 hangs out of the upper surface of the light emittingelement and the adhesive layer having the roughly triangular crosssection makes the reflected light from the side surface of the lightemitting element 3 tend to enter the outer periphery of the phosphorlayer 4, which can improve the light emission brightness of the lightemitting device. Such a hanging out part of the adhesive layer can alsobe formed by adjusting the amount of an adhesive for bonding thetranslucent member with the phosphor layer on its main surface, to theupper surface of the light emitting element, so as to cause theexcessive adhesive whose amount is more than that required for bondingto the upper surface of the light emitting element to hang out to thelight emitting element side surface. Alternatively, by adjusting theamount of binder of the phosphor layer disposed at the translucentmember, the phosphor layer with the binder half-cured is pressed againstthe upper surface of the light emitting element to cause a part of thebinder to extend over the side surfaces of the light emitting element,which can form the hanging out part of the adhesive. The shape of thehanging out part of the adhesive layer can be formed to an optimum shapefor reflecting the light emitted from the side surface of the lightemitting element 3 by optimizing the wettability or viscosity of thesilicon resin to the side surface of the light emitting element or thesurface of the phosphor layer.

In use of the silicone resin in the binder of the phosphor layer 4, theadhesive of the adhesive layer 6 can also preferably use the siliconresin. This arrangement can decrease a difference in refractive indexbetween the phosphor layer 4 and the adhesive layer 6, which canincrease the amount of incident light from the adhesive layer 6 to thephosphor layer 4.

(Semiconductor Element)

The semiconductor elements 5 are disposed adjacent to the light emittingelements 3 over the substrate 2, separately from the light emittingelements 3. Such semiconductor elements 5 can be the same as that usedin the first embodiment.

The height of the semiconductor element in mounting is preferably lowerthan that of the combination of the light emitting element, the phosphorlayer, and the translucent member. This is because the use of thecontour of the semiconductor element can increase the uppermost surfaceof the reflective resin, thereby suppressing the sink of the resin.

(Reflective Resin)

The reflective resin for use in this embodiment can be the same as thatused in the first embodiment.

(Conductive Member)

The conductive member 10 for use can be bumps. Suitable materials forthe bumps can include, Au, or an alloy of Au. Especially, suitablematerials for other conductive members can include eutectic solder(Au—Sn), Pb—Sn, lead-free solder, and the like. Although FIGS. 5A, 5B,and 5C show an example of use of the conductive member 10 as the bump,the conductive member 10 is not limited to the bump, and for example,may be a conductive paste.

(Underfill Material)

The underfill material for use in this embodiment can be the same asthat used in the first embodiment.

(Manufacturing Method)

A manufacturing method of the light emitting device in this embodimentdiffers from the first embodiment in that a step of disposing thereflective resin involves disposing the translucent member with thephosphor layer previously formed on its surface, over the upper surfaceof the light emitting element with the phosphor layer facing toward theupper surface of the light emitting element. FIGS. 6A, 6B, and 6C showexemplary diagrams of an example of steps in the manufacturing method ofthe light emitting device in this embodiment. FIG. 6A shows the step ofdisposing the light emitting elements 3 on the aggregate substrate. Thesemiconductor element 5 is disposed between the adjacent light emittingelements in one of the column and row directions of the arranged lightemitting elements 3. Methods for arranging the light emitting elements 3and the semiconductor elements 5 for use can include flip-chip mounting.Conductive patterns including a positive electrode and a negativeelectrode insulated from each other are formed over the substrate 2. Inmounting, the bumps may be provided on the substrate, or on the lightemitting element 3 and the semiconductor element 5.

Both the p and n electrodes (not shown) of the light emitting element 3are respectively opposed and fixed to both the positive and negativeelectrodes (not shown) formed on the same surface of the substrate 2 viathe conductive members 10. The respective electrodes of the lightemitting element 3 are opposed to the conductive members 10 by applyingheat, ultrasound wave, and loads, so that the light emitting elements 3and the conductive members 10 are coupled to the conductive pattern onthe substrate.

FIG. 6B shows the step of disposing the translucent member with thephosphor layer previously formed on its surface, over each lightemitting element with the phosphor layer side surface facing the uppersurface of the light emitting element. The phosphor layer 4 and thetranslucent member 9 integrally formed via the adhesive layer 6 isdisposed over the upper surface of the light emitting element 3. Theadhesive layer 6 bonds the phosphor layer 4 to the light emittingelement 3. The phosphor layer 4 is formed to be larger than the area ofthe upper surface of the light emitting element 3. The phosphor layer 4is coupled to the light emitting element 3 while having its part exposedfrom and not covered by the upper surface of the light emitting element.In disposing the phosphor layer 4 over the upper surface of the lightemitting element 3, the adhesive hanging out of the upper surface of thelight emitting element 3 is attached to the side surfaces of the lightemitting element 3 and the exposed part of the phosphor layer to therebyform the handing out part of the adhesive layer on the side surfaces ofthe light emitting element 3. The adhesive layer on the side surfaces ofthe light emitting element 3 has a roughly triangular cross sectionwhose thickness is decreased toward the lower part of the light emittingelement 3 in the vertical cross-sectional view. The light emitted fromthe side surfaces of the light emitting element 3 is reflected from theadhesive layer on the side surfaces thereof at an angle in a wide range,which allows the light to easily enter the outer periphery of thephosphor layer 4 to thereby improve the brightness of the light emittingdevice. In the manufacturing process, the adhesive before bonding can beapplied to the phosphor layer side surface of the translucent member, orcan also be applied to the upper surface of the light emitting element.At that time, a part of the adhesive preferably extends to the edgeformed by the side surface of the light emitting element and the surfaceon the light emitting element side of the phosphor layer. Parts of theadhesive layer handing out to the side surfaces of the light emittingelement form the triangular cross-sectional shape.

FIG. 6C shows the step of disposing the reflective resin. The reflectiveresin 8 is disposed along the side surfaces of the light emittingelements 3 and the side surfaces of the phosphor layers 4 andtranslucent members 9. The reflective resin 8 is to reflect lightemitted from the light emitting element 3, and disposed over the sidesurfaces of the light emitting elements 3, and the side surfaces of thephosphor layers 4 and translucent members 9 to cover the entiresemiconductor elements 5.

The semiconductor element 5 is disposed in the intermediate regionbetween the adjacent light emitting elements 3, which results in raisingthe reflective resin 8 by the size of the contour of the semiconductorelement 5 to suppress the sink of the reflective resin 8. Thus, informing the light emitting devices by dividing along the cutting lines12, the width of the reflective layer on the side surface of eachphosphor layer 4 becomes thick as compared to the case without thesemiconductor element 5. As a result, the light from the phosphor layer4 can be sufficiently reflected, which effectively improve thelight-extraction efficiency. The underfill material (not shown) may becharged into gaps between the light emitting element 3 and semiconductorelement 5, and the conductive member 10 and the substrate 2.

Then, the reflective resin 8 and substrate 2 are cut along the cuttinglines 12 shown in FIG. 6C so as to include at least one light emittingelement 3 and one semiconductor element 5 to thereby separate the groupof light emitting devices formed over one substrate 2 into theindividual light emitting devices.

This embodiment has the following effects in addition to the effectsobtained by the first embodiment. That is, the phosphor layer isintegrally formed with the translucent member, and the translucentmember serves as the supporter of the phosphor layer, whereby theconcentration of the phosphor material can be increased withoutincreasing the thickness of the phosphor layer. With this arrangement,the thermal conductivity of the phosphor layer can be improved withoutdecreasing the mechanical strength of the phosphor layer.

Third Embodiment

FIG. 7 is a schematic cross-sectional view showing the structure of alight emitting device C in this embodiment. The light emitting device Chas the same structure as that of the light emitting device of thesecond embodiment except that the adhesive layer of the secondembodiment does not exist in the third embodiment, that a phosphor layer13 contains a thermosetting binder, and that the phosphor layer 13 isfixed directly to the light emitting element 3.

FIGS. 8A, 8B, and 8C are exemplary diagrams showing one example of stepsof a manufacturing method of the light emitting device C in thisembodiment. The manufacturing method of this embodiment can manufacturethe light emitting device in the same way as that of the secondembodiment except that the phosphor layer containing thermosettingbinder is fixed directly to the light emitting element 3 without formingthe adhesive layer.

FIG. 8A shows the step of disposing the light emitting elements over thesubstrate. The light emitting elements 3 are arranged over the aggregatesubstrate. FIG. 8B shows a step of disposing the translucent memberswith the phosphor disposed on its surface, over the respective lightemitting elements. The phosphor layer 13 and the translucent 9integrally formed are arranged over the upper surface of the lightemitting element 3. FIG. 8C shows a step of disposing the reflectiveresin. The reflective resin 8 is disposed along the side surfaces of thelight emitting elements 3 and the side surfaces of the phosphor layers 4and translucent members 9.

The phosphor layer 13 contains the phosphor material and thethermosetting binder. The thermosetting binder is in a half-cured statewith a viscosity at the time when the phosphor layer is formed over thesurface of the translucent member. After disposing the phosphor layerover the upper surface of the light emitting element, the binder isheated and fully cured. The thermosetting binder that can be used forthis embodiment can be, for example, silicone resin.

This embodiment uses a part of the phosphor layer 13 as only an adhesivelayer of the second embodiment, but has the same effects as in thesecond embodiment, and does not require the adhesive layer, which canproduce the light emitting devices at low cost. The light emitted fromthe light emitting element directly enters the phosphor layer, which canimprove the light-conversion efficiency.

EXAMPLES

The present invention will be described in detail below by way ofExamples, but is not limited to the following Examples.

Example 1 Manufacture of Light Emitting Device

In Example 1, the light emitting device shown in FIGS. 3A and 3B wasmanufactured by the method shown in FIGS. 1A, 1B, and 2. Inmanufacturing, the following processes were performed on an aggregatesubstrate, and finally the substrate was singulated into individuallight emitting devices.

First, the substrate 2 with conductive patterns formed on its frontsurface was provided. In this example, a plate-like aluminum nitridesubstrate was used as the substrate 2. The substrate 2 was produced bycalcining an aluminum nitride plate material having a thermalconductivity of about 170 W/mK, and forming the conductive pattern madeof metal, such as Cu, Ni, or Au, over the aluminum nitride plate forestablishing electric connection with the light emitting element. Eachsubstrate had longitudinal and lateral lengths shown in FIGS. 3A and 3Bof about 1.8 mm and about 1.45 mm, respectively, and a thickness ofabout 0.4 mm. The conductive pattern had a thickness of about 2 μm.

Then, the light emitting element 3 and the semiconductor element 5 wereput on the substrate. That is, a plurality of light emitting elementsare arranged in a matrix on an aggregate substrate, and eachsemiconductor element was disposed between the adjacent light emittingelements in one direction of the column and row directions of the lightemitting devices arranged in the matrix. Specifically, the lightemitting element 3 was formed by stacking semiconductor layers over asapphire substrate. Each light emitting element 3 had a substantiallyplanar shape of about 1.0 mm square and a thickness of about 0.11 mm.Then, the semiconductor elements were arranged in columns and flip-chipmounted using bump made of Au with the sapphire substrate sidepositioned as the light emission surface. Further, the semiconductorelements 5 previously provided with bumps made of Au were flip-chipmounted on the conductive patterns.

In this example, as shown in FIG. 2, the semiconductor element wasdisposed between the adjacent light emitting elements in the rowdirection having a larger distance between the adjacent light emittingelements because a distance x (0.75 mm) between the adjacent lightemitting elements in the row direction was larger than a distance y(0.38 mm) between the adjacent light emitting elements in the columndirection.

Then, the phosphor layer 4 was bonded to the upper surface of each lightemitting element 3. In this example, a silicone resin was used as theadhesive material 6, and cured by heat, so that the phosphor layer 4 wasbonded to the sapphire substrate of the light emitting element 3 via abonding surface. The phosphor layer 4 in this example was a phosphorplate of about 0.2 mm in thickness consisting of glass with YAGdispersed thereinto. The area of the lower surface of the phosphor layer4 was larger than that of the upper surface of the light emittingelement 3, and the phosphor layer 4 was bonded to have an exposedsurface from the bonding surface.

Then, the reflective resin 8 was charged into the surroundings of thelight emitting elements 3, the phosphor layers 4, and the semiconductorelements 5. Specifically, the reflective resin 8 was disposed along theside surfaces of the light emitting elements 3 and the phosphor layer 4to completely embed the semiconductor elements 5 in the reflective film8. In this example, the reflective resin 8 used contained about 30% byweight of titanium oxide particles in a dimethyl silicone resin. In thisway, the reflective resin is charged into the gap between the adjacentlight emitting elements, and can be substantially positioned on the sidesurfaces of the light emitting elements, which eliminates the necessityof disposing, for example, a dum along the side surface of the lightemitting element for the purpose of positioning the reflective resinhaving adequate flexibility before being cured.

Then, the substrate 2 subjected to the above-mentioned steps wasaccommodated in and heated by a heating furnace, so that the reflectiveresin 8 was cured. Then, the substrate and the reflective resin were cutalong the cutting line 12 to include the light emitting element 3 andthe semiconductor element 5 which were adjacent to each other toseparate the individual light emitting devices from a group of the lightemitting devices. That is, as shown in FIGS. 1B and 2, the cutting lines12 were set between the adjacent light emitting elements 3 in the rowdirection of the matrix arrangement and between the light emittingelement 3 and the adjacent semiconductor element 5 in the columndirection of the matrix arrangement on the cut substrate to include atleast one light emitting element 3 and one semiconductor element 5.Then, both the reflective resin 8 and the aggregate substrate were cutalong the cutting line 12.

The state of light emission on the light emitting surface is representedby a photograph shown in FIG. 9A when driving the thus-obtained lightemitting device at 900 mA. The light emitting surface had a high surfacebrightness and uniform brightness distribution, whereby four sidesurfaces of the light emitting surface were clearly observed.

The photographs of the cross-section of the thus-obtained light emittingdevice is shown in FIG. 10. As can be seen from the photograph, the sinkof the reflective resin (white part) is largely suppressed. Further, thecorner formed by the reflective resin side surface on the semiconductorelement side and the upper surface of the reflective resin forms anacute angle (81.57°) in the vertical cross-sectional view including thelight emitting element and the semiconductor element. Also, the cornerformed by the reflective resin side surface on the light element sideand the upper surface of the reflective resin forms an obtuse angle(106.93°) in the vertical cross-sectional view including the lightemitting element and the semiconductor element.

Comparative Example 1

In the same way as in Example 1, except that the semiconductor elementwas not disposed over the substrate, a light emitting device wasmanufactured. The light emission state of the light emitting surface isshown in the photograph of FIG. 9B. The light emitting surface had a lowsurface brightness and non-uniform brightness distribution (especially,its end being dark), whereby the outlines of four side surfaces of thelight emitting surface were vague.

Example 2 Manufacture of Light Emitting Device

In Example 2, the light emitting device shown in FIGS. 5A, 5B, and 5Cwas manufactured by the method shown in FIGS. 6A, 6B, and 6C. Inmanufacturing, the following processes were performed on an aggregatesubstrate, and finally the substrate was singulated into individuallight emitting devices.

In the same way as in Example 1, the substrate 2 with conductivepatterns formed on its front surface was provided.

Then, in the same way as in Example 1, the light emitting element 3 andthe semiconductor element 5 were put on the substrate.

Apart from the above-mentioned steps, the phosphor layer 4 was appliedto the surface of the translucent member 9, that is, one entire mainsurface thereof by printing. A plate-shaped molded member made ofborosilicate glass was used as the material for the translucent member9. Each translucent member had a substantially square planar shape ofabout 1.15 mm square, and was larger by about 0.15 mm in each of thelongitudinal and lateral sizes than the planar size of the lightemitting element. The translucent member had a thickness of about 0.15mm. The translucent member with the phosphor layer 4 formed thereat wasformed by printing a mixture of two kinds of phosphor materials of(Sr,Ca)AlSiN₃:Eu, and Y_(2.965)Ce_(0.035)(Al_(0.8)Ga_(0.2))₅O₁₂ with asilicone resin as a binder, onto one main surface of the plate-shapedtranslucent member, and cutting the translucent member with the phosphorlayer into an appropriate size. The concentration of the combination ofthe two phosphor materials in the phosphor layer 4 was 90% by weight.The phosphor layer facing the upper surface of the light emittingelement had a substantial square planar shape of about 1.15 mm square,like the planar shape of the translucent member, and a thickness of 90μm.

Then, a silicone resin was disposed as the adhesive on the upper surfaceof the light emitting element 3, whereby the phosphor layer 4 formed atthe translucent member was bonded to the upper surface of the sapphiresubstrate of the light emitting element 3. The area of the surface ofthe phosphor layer 4 on the light emitting element side surface waslarger than that of the upper surface of the light emitting element 3,and the phosphor layer 4 was bonded to have an exposed surface from thebonding surface.

Then, the reflective resin 8 was charged into the surroundings of thelight emitting elements 3, the phosphor layers 4, the phosphor layers 9,and the semiconductor elements 5. Specifically, the reflective resin 8was disposed along the side surfaces of the light emitting elements 3,phosphor layers 4, and translucent members 9 to completely embed thesemiconductor elements 5 in the reflective film 8. In this example, thereflective resin 8 used contained about 30% by weight of titanium oxideparticles in a dimethyl silicone resin.

Then, the substrate 2 subjected to the above-mentioned steps wasaccommodated in and heated by a heating furnace, so that the reflectiveresin 8 was cured. Then, the substrate and the reflective resin were cutalong the cutting line 12 to include the light emitting element 3 andthe semiconductor element 5 which were adjacent to each other toseparate a group of the light emitting devices into the individual lightemitting devices.

When the thus-obtained light emitting device was driven at 900 mA, thelight emitting surface had a high surface brightness and uniformbrightness distribution.

The methods for manufacturing a light emitting device of the presentinvention can be applied to manufacture light emitting devices that canbe used for a display device, an illumination tool, a display, abacklight source of a liquid crystal display, and the like.

What is claimed is:
 1. A method for manufacturing a light emittingdevice, the light emitting device comprising a light emitting elementdisposed over a substrate, and a reflective resin disposed along a sidesurface of the light emitting element, the method comprising the stepsof: disposing a plurality of light emitting elements in a matrix over anaggregate substrate, and disposing a semiconductor element other thanthe light emitting element in between the adjacent light emittingelements in one direction of column and row directions of the lightemitting elements disposed in the matrix; after disposing phosphorlayers over the respective upper surfaces of the light emittingelements, disposing a reflective resin along the side surfaces of thelight emitting elements and the side surfaces of the phosphor layers tocover the semiconductor elements; and simultaneously cutting thereflective resin and the substrate disposed in between the adjacentlight emitting elements in one of the column and row directions andbetween the light emitting element and the semiconductor elementadjacent thereto in the other direction of the column and row directionsso as to include at least one light emitting element and onesemiconductor element, wherein, in the step of cutting, cutting isperformed in a vertical direction including the light emitting elementand the semiconductor element such that a corner formed by a sidesurface of the reflective resin on the semiconductor element side and anupper surface of the reflective resin forms an acute angle in across-sectional view.
 2. The method for manufacturing a light emittingdevice according to claim 1, wherein the semiconductor element isdisposed between the light emitting element and another adjacent lightemitting element having a larger one of a distance between the adjacentlight emitting elements in one direction of the column and rowdirections and another distance between the adjacent light emittingelements in the other direction of the column and row directions.
 3. Themethod for manufacturing a light emitting device according to claim 1,wherein in the step of cutting, cutting is performed such that anothercorner formed by a side surface of the reflective resin on the lightemitting element side and the upper surface of the reflective resinforms an obtuse angle in the cross-sectional view.
 4. The method formanufacturing a light emitting device according to claim 1, wherein adeepest part of a recessed portion formed at the upper surface of thereflective resin is formed directly above the semiconductor element. 5.The method for manufacturing a light emitting device according to claim4, wherein the deepest part of the recessed portion formed at the uppersurface of the reflective resin is formed directly above a center of theupper surface of the semiconductor element.
 6. The method formanufacturing a light emitting device according to claim 1, wherein anadhesive layer is formed such that, in the vertical cross-sectional viewof the side surface of the light emitting element, the adhesive layerextends at a corner formed by the side surface of the light emittingelement and the surface on the light emitting element side of surface ofthe phosphor layer, and such that the adhesive layer has a roughlytriangular cross section so that the thickness of the adhesive layer isdecreased toward the lower part of the light emitting element.